The present invention relates in general to wireless mobile ad hoc networks. More specifically, the invention relates to a method and apparatus for providing a routing protocol for wireless mobile ad hoc networks that produces an enhanced Quality-of-Service support from the network.
Routing protocols for wireless mobile ad hoc networks (hereinafter “MANETs”) have been extensively explored in recent years. Most of the work completed thus far, however, has focused on finding a feasible route from a source to a destination in a timely and efficient manner without considering the impact on the transport performance of existing application traffic or the newly added flows. As a result, parts of the network may become saturated with no means of automatically compensating or routing traffic around the overloaded areas, which results in a lowering of network efficiency. While this limitation may be tolerable for best-effort or delay-tolerant data transfers, real-time applications require a certain level of Quality-of-Service (hereinafter “QoS”) from the network. Accordingly a comprehensive MANET QoS solution would benefit from a QoS-aware routing scheme that takes into account the application's transport requirements and the data transport conditions of available data paths through the network.
Some QoS architectures include a resource reservation function where network resources such as link bandwidth and queue size are allocated to ensure the timely transport of user data. A typical resource reservation process has two essential steps: a) finding resources; and b.) making reservations. Resource reservation can only be made when a routing protocol has found paths with sufficient resources to meet user requirements. User data QoS requirements and the transport capabilities of the path must therefore be taken into consideration when making a path selection.
In traditional data networks, routing is primarily concerned with connectivity. Examples of conventional routing protocols and techniques can be found in the following references, the contents of each of which is incorporated herein by reference: U.S. patent application Ser. No. 11/546,783, filed on Oct. 12, 2006, entitled Adaptive Message Routing for Mobile Ad Hoc Networks; U.S. patent application Ser. No. 11/897,474, filed Aug. 30, 2007, entitled Topology Aware MANET for Mobile Networks; Load-Balanced Short-Path Routing in Wireless Networks, Jie Gao, Li Zhang, IEEE Transaction On Parallel and Distributed Systems, VOL. 17, NO. 4, April 2006; A Survey of Routing Techniques for Mobile Communications Networks, S. Ramanathan and M. Steenstrup, Mobile Networks and Applications, vol. 1, no. 2, pp. 89-104, 1996; H. Kopetz, W. Schwabl, Global Time in Distributed Realtime Systems. Technical Report 15/89, Technishe Univesität Wien, 1989; The Optimized Link-State Routing Protocol version 2 draft-ietf-manet-olsrv2-02, T. Clausen, C. Dearlove, P. Jacquet; Dynamic MANET On-demand (DYMO) Routing draft-ietf-manet-dymo-05, I. Chakeres, C. Perkins.
Conventional routing protocols usually characterize the network with a single metric, such as hop-count or delay, and use shortest-path algorithms for path computation. In order to support a wide range of QoS requirements, however, routing protocols need to have a more complex model where the network is characterized with multiple metrics such as available bandwidth, delay, and loss probability. The basic problem of QoS Routing then is to find a transmission path that satisfies multiple constraints while maximizing residual network resources and still meeting transport requirements of the offered load; i.e., consume the smallest amount of network resources to convey the traffic within the required performance parameters. Accordingly, a need exists for an apparatus and method to improve QoS Routing to find a path that satisfies multiple constraints.